Generated YAML and SQL code should conform to dbt Labs style guide

### Describe the feature

Any YAML or SQL generated by `codegen` should adhere to these style guides:
- [How we style our YAML](https://docs.getdbt.com/best-practices/how-we-style/5-how-we-style-our-yaml)
- [How we style our SQL](https://docs.getdbt.com/best-practices/how-we-style/2-how-we-style-our-sql)

### Additional context

See https://github.com/dbt-labs/dbt-codegen/pull/74/files#r944596657 for the instigating thread.

For example, here is our current and original style guides for CTEs (`with` statement):
- [Current](https://docs.getdbt.com/best-practices/how-we-style/2-how-we-style-our-sql#import-ctes)
- [Original](https://github.com/dbt-labs/corp/blob/08c3799c7c62fa618e3105362cf0c020c17d3ee8/dbt_style_guide.md#ctes) (just for historical context of any changes over time)

### Who will this benefit?

This will avoid confusion for users that see one thing recommended as a best practice or adopted style guide, but then see something else auto-generated by this package.

Start at the `codegen` generation entry points and compare their YAML and SQL output with the linked dbt Labs style guides, including the CTE guidance. Done means generated YAML and SQL consistently follow those current guides; use the linked pull request discussion for the original context.

Written by the indexing model from the issue text.